Magnetic recording and reproducing



July 31, 1945. s .1. BEGUN 2,380,392

MAGNETIC RECORDING AND REPRODUCING Filed July 21, 1943 SEMI JOSEPH ill/V, INVENTOR.

BY M Patented July 31, 1945 UNITED STATES PATEN zssosaz 'r caries MAGNETIC RECORDING AND BEPRODUCING Semi Joseph Begun, Cleveland Heights, Ohio, as-

signor to Magnetone Inc., Cleveland, Ohio, a

corporation of Ohio Application July 21,

7 Claims.

.tion will be best understood from the following description of exempliilcations thereof, reference being had to the accompanying drawing which is a diagrammatic view of the circuits and the operrecording carrier shown in the form of a lpng endless magnetic tape 8i driven at uniform speed in clockwise direction, for instance.

The signal recorded on each element of the moving endless tape remains thereon until, after a predetermined supervision time delay, the recorded element of the endless tape reaches a playback head .l-P, the output coil of which is connected to the modulator and radio broadcast transmitter TR. so as to bring about the broad.-

cast of the message from the microphone in .the

same way as if ithad been directly supplied to the radio broadcast transmitter, but with the predetermined supervision time delay.

An obliterating head shown in the form of a permanent magnet, is placed before the recording head l-R to assure that each carrier element reaching the recording head 4-8 is ready to receive a new recording. The equipment thus far described. constitutes a signal transmission channel of a signal transmission system including an endless magnetic carrier and signal transdusing means associated therewith so that messages supplied by the signal input means. such as the microphone MC, are transmitted to signal output means, such as the radio transmitter TR, with a predetermined time delay. a

The equipment for supervising or censoring the transmitted message has a sequence of alike Ill,-

1943, Serial no. 495,801

(on. ire-100.2) v

pervising stations, a sequence of two censoring stations CA, CB being shown for the sake of simplicity. Each censoring station is provided with a set or four push button switches K, Li, L2, L8, and with headphones 8!, a signaling lamp 82 and auxiliary switching elements for performing the various operations as explained hereinafter.

Assuming, for instance, that the supervising station CA is activated, and keeps on supervising 10 the transmitted message, the supervisor keeps the push button switch Li of his station actuated and the headphones 8| of his station are connected through the switch contacts to shoutput lead 83 from the amplifier 1A, so asd'o enable is him to listen to the transmitted message as it for subsequent transmission, after the time delay determined by the location of the recording head 4B and the pickup head 4-? along the path so of motion of the endless magnetic tape, for in stance, one or two minutes. to the radio broadcast transmitter'I'B. a Upon releasing the push button Li andactuating the push button L2, the censorat each staas tion' may connect his headphones to the output lead of a playback amplifier AM-i upon which is impressed the outputiof a playback head located on an intermediate portion of the tape so as to enable the censor, if. after listening to the transmitted messase, he, realizes that it contains objectionable matter, to pickup the starting phrase of the message so as to enable him to can- 4-? to the radio broadcast transmitter an.

After having thus picked up the starting phrase of the obiectional message, the censor has merely to release the push button L2, and by .actuating push button LI, connect his headphones 8| to the output lead from amplifier AM-I which amplifies the output of a third playback head 4-?! placed a distance ahead of the main playback head 4-1, and as soon as he hears the initial phrase of the objectionable message, he has merely to push button K which completes a circuit sending an obliterating, current to the obliterating head, 4-03 placed of the main playback head L-P, thereby cancelling the message recorded on the tape and preventing its transmission when the elements of the tape on which it was recorded pass through the. main.

system eiieomust be is being recorded on'the endless magnetic tape Ii eel the entire objectionable message beiore it can I be transmitted from the main playback head a sequence of at least two censoring stations.

provided is lighted by a circuit completed through the con tact of a stepping switch 88 having an operat ng coil 81, which, upon energization, advances the contact 01' the stepping switch one step. thereby cutting out the'signal lamp of station 'A and lighting up the signal lamp of station B. indicating to the censor or the latter station that 'it'is his duty to watch the transmitted message by closing his push button switch Li.

With this arrangement, censor A. whose si naling lamp 02 is lighted and has his push button Ll operated to listen to the transmitted message. on noticing that the message contains objectionable matter, merely releases the push button LI and actuates the push button M. which immediately connects his headphone to the intermediate playback head l-.P2 for enabling him head prices to the playback head a-rs me be ready to cancel the message as soon as he hearsthe initial phrase oi the message in uestion, whereupon he actuateshis cancelling button switch K which completes a circuit sending an oblitearating current to the obliterating head Locking means are also provided for preventing accidental obliteration of a message that is beins transmitted. Inthe arrangement shown, the obliterating push button switches K are normally held locked by a locking relay 8i having a latch in the manner described above.

to pickup the starting phrase of the objectionab e message. On closing his push button switch L2. the censor at station A also completes a circuit, including the normally closed contacts or an interlocking auxiliary relay 8. to the operatin coll I1 oithe stepping switch, thereby advancing it, to the next stop in which his own signal lamp II is extinguished and the signal lamp 82 01' the other censor islighted up. whereupon the censor B actuates his push button switch connecting his own headphones to the amplifier IA for watching the transmitted message.

Each of censor stations CA. CB is shown provided with interlocking means for assuring that when one censor station starts tracing the objectionable-matter and attends to its cancellation. onlyone signaling operating operation is transmitted tothe other, or next, censor station to start listening in to the messages that are being transmitted. In the arrangement shown, the interlocking means of each'station is formed by the time delay relay 88 arranged so that-when either one of switchesm or L3 is actuated to listen in to the recorded objectionable messagethere isestablished not only an instantaneously operative circuit to the stepping coil 81 of the stepping'relay it, which lights up the signal lamp of, or otherwise activates the next censoring station, such as CB, but also an interlocking circuit to the time-delay interlocking relay 8!, which opens itscontacts after a predetermined time delay, thereby interrupting the signaling circuit to the stepping magnet through which the next station 1158 Just been activated. The interlocking relay 8. or each censoring station is designed to have a time delay in opening and a time delay in closing of a sufiiciently long time to assure that during the time interval between releasing the listening in switch L2 0! pickup head 4-?! and actuation or the listening switch Ll oi' the next pickup head l-PI, the contacts of the switch II will remain open andprevent transmission ot another activation signal to the next censoring station.

The censor at station A. upon having picked up the beginning phrase oi the objectionable message. will release his push button LI and actuate hispushbuttonswltchusoss toconnocthis The contact arm or the obliterating switch K is biased to return when released to its open position, and the latch arm I! is normally biased to return to the locking position shown, the latch projections 93, ll 01' the locking means and their associated elements being so shaped and arranged that the contact arm oi'the obliterating switch K is i'ree to return to its open position shown whenever it is released, no matter whether the switch Ll'is in the non-actuated position shown, or in its actuated position.

The foregoing arrangement provides thus a ioolproot censoring system, which prevents undesirable interference with the transmitted message and permits tracing of an objectionable part of the message while its transmission is delayed, as well as the selective obliteration of the objectionable message part before it is being transmitted.

Obviously, a larger number of message tracing playback heads, such as 4-?! may be provided for enabling the censor to pick up diilerent parts of the message which are stored in the endless tape, while they are being advanced from the recording head lR,-during the time interval of the time delay cycle, to the point where they are picked up by the playback head l-P for delivery to the radio broadcast transmitter TR.

The supervising or censoring arrangement described above represents a signal channel formed by th endless magnetic carrier 8i and the-associated transducing means and constituting an interconnection between the signal input means, represented by the microphone MC, and the signal output means, represented by the radio transmitter TR, for transmitting through the channel and delivering to the transmitter a series of signal sequences supplied by the microphone MC. The signal transducing means associated withthe carrier are'formed oi th various transducer elements l-R, l-PI, l-Pl, 4-08, 4-1, 4-0 located along the path of the carrier for recording, reproducing and obliterating, respectively, the signal sequences recorded on the carrier as it moves past the transducing means.- a

At least one signal recording element, represented by the recording element l-R. serves to record on a portion or the endless carrier moving past it the signal sequence as it is being supplied thereto by the microphone MC. Each element of therecorded signal sequence is reproduced with a predetermined time delay by the transmission pickup element 4-? which supplies reproduced signals to the transmitter TR.

In order tosupervise'the transmission of the signal sequence, the endless signal carrier is also provided with supervising means formed of a supervising set-up which, in the arrangement shown, is composed of two pickups 4-H and 4P3, the two pickup elements 4-92 and 4-?! being located alongspaced intermediate portions of the path of the endless carrier.

The supervising means also include at least two supervising se t-ups, represented by the supervising set-ups CA, CB, each supervising set-up including switches Ll L2, L3 for-selectively translating the recorded message either as directly supplied by the microphone or as reproduced by one of the'pickups into an observable sound signal sequence reproduced by the translating means, represented by the receiver 8|.

In addition, each of the supervising set-ups includes canceling means provided with an obliterating element located along a portion of the carrier path extending between the transmission pickup element 4P and the next preceeding pickup element 4-P3 for enabling selective obliteration of the recorded signal before it is picked up by the transmission pickup element l-P;

The supervising means are also provided with activating means automatically operative when an active supervising set-up starts to .trace the objectionable message to activate another super- =vising set-up by givingit a signal to take over the further supervising action, the activating means being represented by the selector switch 86 and -objectionable signal sequence which has been the signaling lamps 82 which are automatically actuated when one of the supervising set-ups stops the supervising action and starts tracing the objectionable message, and brings about its cancellation. I

The automatic activating means are also pro vided with automatic locking means which are operative in response to the actuation of one of the switches L2, L3 associated with the translating means of the supervising set-up for preventing sending out of more than one activating signal to another supervising set-up of the supervising equipment, the interlockingmeans being represented by the time-action relays 88 and the associated circuit elements.

recorded on the carrier and has been reproduced by a selected pickup element during an interval between the actuation of the cancellation starting element and the actuation terminating element.

The automatic canceling means may utilize any form of known time-action means which are so designed asto perform a timing action correlated to' the time during which a carrier element moves from one of the pickup elements-which is being used to trace the message to be cancelled-to the obliterating element 4-03.

In order to :prevent the discontinuity formed by a soldering joint, such as 39, from interfering with the censoring operation, a censoring system of the invention may be built as follows: The endless magnetic signal carrier is arranged to move along a path formed'of a plurality of path sections such as indicated in Fig. 1 of my application Serial No. 370,417, filed December 16, 1940-and represented .there by the three sections of the carrier associated with the recording heads RA, RB, RC, respectively,

Each of the carrier path sections is in turn provided with a complete set of transducing elements, such as represented by the transducing elements 4,-R, lP2, 4'-P3, 4-03, 4P and 4--0 shown in the drawing of the present application and interconnected in the same manner so that each signal sequence supplied by the microphone MC is simultaneously recorded by two recording elements 4--R on two different sections of the carrier path, respectively, and similarly reproduced and supplied to the radio transmitter TR from two transmission pickup elements k-P associated with the two carrier path sections.

Each of the carrier path sections is also providedwith automatic signal suppression means associated with a switch it actuated by a carrier signal 39 in the'same manner as corresponding elements 3|, 5| of my aforesaid application Each supervising system is also provided with preventing means, represented by the relay 9| and the interlocking elements 92, 93,- 95 associated vwith the supply of current to the obliterating current 4-03 so as to prevent the obliteration of the recorded sound sequence carried by the elements of the carrier as they move along the path from the recording element 4-R to the transmission element 4P, unless. the supervising means have been activated to reproduce the signal by a pick up element, such as pickup element 4P3 locatedalong the path of the carrier proceeding the portion along which the transmission pickup 4-1? is plied signal sequences:

Serial No. 370,417 serve to suppress the reproduced signal that is to be transmitted when a discontinuity of the carrier passes through the transmission pi k'up element.

It will be ap arent to those skilled in the art that the novel principles of the invention disclosed herein in connection with specific exempliflcations thereof will suggest various other modifications and applications of the same. It is accordingly desired that in construing the breadth of the appended claims they shall not be limited'to the specific exemplifications of the invention described herein.

I claim: n

1. In a signal-transmission system having signal input means for supplying signal sequences and signal output means for delivering the supa signal: transmission channel interconnected between said signal input means and signal output means and including an endless magnetic signal carrier for magnetically recording thereon and reproducing therefrom signals while the elements of said carrier are impelled along a predetermined carrier path; signal transducing means including a set of transducing elements located along said path for recording or reproducing a signal sequence while said carrier moves past said transducing means; said set of transducing elements including at leastone recording element located along one portion of said path for recording on the carrier signal sequences supplied by the input means the signals reproduced by said intermediate pickup element; into an observable signal; and canceling means for obliterating the signal recorded on said carrier before it is reproduced by said transmission pickup element; said canceling means including an obliterating element located along a portion of said path extending between said transmission pickup element and the proceeding pickup element, said canceling means including means for performing-atiming action correlated to the time during which a carrier element moves from one of the pickup elements to the obliterating element and having a cancellation starting element actuable when the initial portion of a characteristic signal sequence is observed and a cancellation stopping element actuable when the end portion of a characteristic signal sequence is observed, for causing said canceling means to obliterate the signal sequence which has been recorded on said carrier during the interval between the actuation of said starting element and the actuation of said terminating element;

2. In a signal transmission system having signal input means for supplying signal sequences and signal output means for delivering the supplied signal sequences: a signal transmission channel interconnected between said signal input means and signal output means and including an endless magnetic signal carrier for magnetically recording thereon and reproducing therefrom signalswhile the elements of said carrier are impelled along a predetermined carrier path; signal transducing means including a set of transducing elements located along said path for recording or reproducing a. signal sequence while said carrier moves past said transducing means; said set of transducing elements including at-least one recording element located along one portion of said path for recording on the carrier signal sequences supplied by the input means and transmission means having a transmission pickup element located at another portion of said path for reproducing from said carrier signals recorded thereon by said recording element with a predetermined time delay, and means for transmitting the reproduced signals to said output means; supervising means including a sequence of at leasttwo supervising setups for supervising the signal sequences of said source transmitted through said channel; each of said supervising set-ups including at least two intermediate pickup elements located along spaced intermediate portions of said path; translating means including selectively operative actuating means for selectively translating the signals reproduced by said intermediate pickup elements into an observable signal; and canceling means including an obliterating element located along said path between said transmission pickup element and the preceding pickup element for obliterating the signal recorded on said carrier before-it is reproduced by said transmission pickup element; and signalling means interconnecting said two set-ups operative in response to the actuation of one set-up for signalling its actuation to the other set up.

3. In a signal transmission system having signal input means for supplying signal sequences and signal output means for delivering the supplied signal sequences: a signal transmission channel interconnected between said signal input means and signal output means and including an endless magnetic signal carrier for magnetically recording thereon and reproducing therefrom signals while the elements of'said carrier are impelled along a predetermined carrier path; signal transducing means including a set of transducing elements located along said path for recording or reproducing a signal sequence while said carrier moves past said transducing means; said set of transducing elements including at least one recording element located along one portion of said path for recording on the carrier signal sequences supplied by. the input means and transmission means having a transmission pickup element located at another portion of said path for reproducing from said carrier signals recorded thereon by said recording element with a predetermined time delay, and means for transmitting thereproduced signals to said output means; supervising means including a sequence of at least two supervising setups for supervising the signal sequences of said source transmitted through said channel; each of said supervising set-ups including at least two intermediate pickup elements located along spaced intermediate portions of'said path; translating means including selectivelyoperative' actuating means for selectively translating the. signals reproduced by said intermediate pickup elements into an observable signal; canceling means including an obliterating element located along said path between said transmission pickup element and the preceding pickup element for obliterating the signal recorded'on said carrier before it is reproduced by said transmission pickup element; signalling means interconnecting said two set-ups operative in response to the actuation of one set-up for signalling its actuation to the other set-up; and activating means operative in response to the actuation of the translating means of one supervising set-up for supplying an activating signal to another supervising set-up. I

4. A signal transmission system as defined by claim 3, which has interlocking means for preventing the transmission of more than one activating signal by a supervising set-up while to prevent the operation of the canceling means while the translating meansare inactive next to said transmission pickup element.

6. A signal transmission system as defined by claim 3, characterized by the fact that the canceling means include means for performing a timing action correlated to the time during which a carrier element moves from one of the pickup elements to the obliterating element and having a cancellation starting element actuable when the initial portion of a characteristic signal sequence is observed and a cancellation stopping element actuable when the end portion of a characteristic signal sequence is observed,

for causing said canceling means to obliterate I tuation of said starting element and the actuation of said terminating element.

'7. In a signal transmission system having signal input means for supplying signal sequences and signal output means for delivering the supplied signal sequences: a signal transmission channel interconnected between said signal input means and signal output means and including an endless magnetic signal carrier for magnetically recording thereon and reproducing therefrom signals while the elements of said carrier are impelled along a predetermined carrier path; said path having at least two path sections; signal transducing means including one set of transducing, elements located along one section of said path and at least one other set of transducing elements located along another section of said path for recording or reproducing a signal sequence while said carrier moves past said transducing means; each of said sets .of transducing elements including at least one recording element located along one portion of said path section for recording on the carrier signal sequences supplied by the input means and transmission means having a transmission pickup element located at another portion of said path section for reproducing from said carrier signals recorded thereon by said recording element with a predetermined time delay, and means for transmitting the reproduced signals to said output means; supervising means including a sequence of at least twosupervising setups for supervising the signal sequences of said source transmitted through said channel; each of said supervising set-ups including at least one intermediate pickup element located along an intermediate portion of said path section; translating means including selectively operative actuating means for selectively translating the signals reproduced by said intermediate pickup elements into an observable signal; and canceling means including an obliterating element located along said path section between said transmission pickup element and the preceding pickup element for obliterating the signal recorded on said carrier beforeit is reproduced by said transmission plckup element and signalling means interconnecting said two set-ups operative in response'to the actuation of one set-up for signalling its actuation to the other set-up.

SEMI JOSEPH BEGUN. 

